GB17740-2017
General ruler for earthquake magnitude
地震震级的规定
GB 17740-2017 is a current mandatory Chinese national standard for General ruler for earthquake magnitude. It appears in the Construction compliance cluster with a product safety focus and has an implementation date of Dec 1, 2017.
Applicability depends on product scope, certification route, competent authority notices and transition rules. Requst for the translation or verify source before using this record in a compliance decision.
Compliance overview
Scope and applicability
This standard specifies the measurement methods and usage rules for earthquake magnitude. It applies to earthquake monitoring, emergency response, information release, science popularization, and news reporting. This standard is mandatory for all seismic networks and related agencies involved in earthquake information dissemination, but it does not apply to other types of magnitudes used in scientific research.
Technical requirements
The standard defines the measurement methodologies for various types of earthquake magnitudes, including local magnitude (ML_), surface wave magnitude (MS_), and moment magnitude (Mw_). It outlines the specific formulas and parameters required for calculating each magnitude type based on seismic wave records. Seismic networks must measure all possible magnitudes without converting them into one another. It also establishes strict rules for magnitude publication. For rapid earthquake information reports, moment magnitude (Mw_) should be prioritized if the seismic moment can be determined promptly. If the seismic moment cannot be determined in time, specific magnitude types must be selected based on earthquake depth and magnitude range. Furthermore, the standard mandates that the published magnitude be represented simply as "M" without additional descriptive terms like "Richter magnitude" or "moment magnitude". All levels of government and news media must use this unified published magnitude for emergency response and public communication.
Testing methods
The standard details the measurement procedures using simulated short-period and medium-long-period seismograph records. Key methods include measuring the maximum amplitude of S-waves for local magnitude and the maximum ground motion velocity of surface waves for broadband surface wave magnitude. Calibration functions and specific instrument transfer functions must be applied as specified in the normative appendices.
FAQs
What systems or organizations are regulated under GB 17740-2017?
It regulates seismic monitoring networks, earthquake information systems, government agencies, and news media outlets involved in earthquake reporting and emergency response in China.
Are there any updates from the previous version of GB 17740-2017?
Yes, compared to GB 17740-1999, this version adds 16 new terms, introduces measurement methods for broadband and moment magnitudes, and modifies the rules for magnitude publication.
How should the earthquake magnitude be presented to the public according to GB 17740-2017?
The externally published magnitude must be represented simply as "M" without any additional prefixes or descriptive terms like "Richter" or "moment".
The summary above provides a high-level overview of GB 17740-2017. To ensure complete compliance for your seismic monitoring systems or reporting protocols entering the Chinese market, a precise and professional translation of the full technical specifications is essential. Purchase our high-quality English translation of GB 17740-2017 today to access all detailed parameters, formulas, and calibration tables.
Applicability hints
- Type
- Foundational
- CCS
- P15
- ICS
- 91.120.25
- Competent department
- China Earthquake Administration
- Technical committee
- National Technical Committee on Earthquake of Standardization Administration of China
Relationships
Replaces:GB 17740-1999